DP-900 Describe core data concepts Practice Question
A company stores customer transaction data in Azure Blob Storage. They need to query the data using SQL-based tools without moving the data. Which Azure service should they use?
⚠ Common exam trap
Many exam-takers confuse Azure Synapse Serverless SQL pool with Azure SQL Database, assuming any 'SQL' service can query external storage, but only Synapse Serverless SQL pool provides native external data querying over Blob Storage without data movement.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Azure Synapse Serverless SQL pool
Azure Synapse Serverless SQL pool allows you to query data directly from Azure Blob Storage using T-SQL without moving or copying the data. It uses a pay-per-query model and supports reading common file formats like Parquet, CSV, and JSON, making it ideal for ad-hoc querying over data lakes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a fully managed relational database engine with its own storage and transaction log. While it supports tools like BULK INSERT or OPENROWSET to read from Blob Storage, these operations physically copy the file's contents into database tables or memory before any query can execute. It does not allow you to write a T-SQL query that directly and repeatedly scans the original file in Blob Storage without loading the data first, so it is not a true query-in-place solution for raw files.
- ✗
Azure Analysis Services
Why it's wrong here
Azure Analysis Services is a BI semantic modeling service that exposes tabular or multidimensional models via DirectQuery or in-memory modes. DirectQuery in Analysis Services requires a supported relational data source such as SQL Server, Azure SQL Database, or Azure Synapse Analytics; it cannot connect to arbitrary files in Blob Storage as a source. Even though it can query external data, its job is to enrich and present data from databases, not to parse CSV or Parquet files directly from a storage container, so it cannot address the requirement of querying transaction files in place.
- ✗
Azure Cosmos DB
Why it's wrong here
Azure Cosmos DB is a NoSQL database with a SQL-like query language that operates on JSON documents stored inside its own containers, backed by its own index and storage engine. Cosmos DB's query APIs are designed to retrieve items from a container, not to scan external files in Blob Storage, and there is no built-in support for reading CSV or Parquet files as external tables. To use Cosmos DB for this scenario you would have to migrate or ingest the transaction data into a collection, which is exactly the kind of data movement the prompt wants to avoid.
- ✓
Azure Synapse Serverless SQL pool
Why this is correct
Azure Synapse Serverless SQL pool is a distributed query engine built into Azure Synapse Analytics that lets you run T-SQL queries directly over files in Azure Blob Storage and Data Lake Storage Gen2. It uses the OPENROWSET function and supports external tables to transparently read CSV, Parquet, and JSON files without copying the data into a database. You simply point the query at the storage location, define the file format and schema, and the pool returns results by scanning the files on demand, making it the correct choice for ad-hoc, in-place analysis of customer transaction data.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Data Roles and Core Concepts
Key term
Serverless SQL pool
Serverless SQL pool is an on-demand, pay-per-query analytics service in Azure that lets you query data stored in data lakes without provisioning or managing any dedicated infrastructure.
Key term
Blob storage
Blob storage is a cloud service for storing large amounts of unstructured data, such as text or binary data, like documents, images, and videos.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-900 exam.